Recently, there has been demand for further integration and reduction in size and cost of cellular phones, terminal devices for wireless communication or the like, and so forth.
In accordance with this, semiconductor devices in which a core portion, an input/output circuit, a power amplifier circuit, and so forth are mounted on the same semiconductor substrate have been brought to attention.
A transistor of the core portion or input/output circuit portion may be formed by a common CMOS process.
On the other hand, voltage which is triple that of gate bias voltage or so may be applied to a transistor used for the final stage of a power amplifier circuit, or the like. Therefore, it is desirable for a transistor used for the final stage of the power amplifier circuit, or the like to have secured sufficient withstand voltage.
However, there has been a problem wherein, in the event that transistors having markedly different withstand voltage are to be mounted on the same substrate, this causes increase in number of processes.
Related art is disclosed in Japanese Laid-open Patent Publication No. hei6-310717, Japanese Laid-open Patent Publication No. 2002-270825, US Laid-open Patent Publication No. 2007/0212838, and so on.